package com.whiteape.book.utils;

public class SimilarityUtil {

    private static int min(int one, int two, int three) { 
        int min = one; 
        if(two < min) { 
            min = two; 
        } 
        if(three < min) { 
            min = three; 
        } 
        return min; 
    } 
    
    public static int ld(String str1, String str2) { 
        int d[][];    //矩阵 
        int n = str1.length(); 
        int m = str2.length(); 
        int i;    //遍历str1的 
        int j;    //遍历str2的 
        char ch1;    //str1的 
        char ch2;    //str2的 
        int temp;    //记录相同字符,在某个矩阵位置值的增量,不是0就是1 
        if(n == 0) { 
            return m; 
        } 
        if(m == 0) { 
            return n; 
        } 
        d = new int[n+1][m+1]; 
        for(i=0; i<=n; i++) {    //初始化第一列 
            d[i][0] = i; 
        } 
        for(j=0; j<=m; j++) {    //初始化第一行 
            d[0][j] = j; 
        } 
        for(i=1; i<=n; i++) {    //遍历str1 
            ch1 = str1.charAt(i-1); 
            //去匹配str2 
            for(j=1; j<=m; j++) { 
                ch2 = str2.charAt(j-1); 
                if(ch1 == ch2) { 
                    temp = 0; 
                } else { 
                    temp = 1; 
                } 
                //左边+1,上边+1, 左上角+temp取最小 
                d[i][j] = min(d[i-1][j]+1, d[i][j-1]+1, d[i-1][j-1]+temp); 
            } 
        } 
        return d[n][m]; 
    } 
    
    public static double sim(String str1, String str2) { 
        int ld = ld(str1, str2); 
        return 1 - (double) ld / Math.max(str1.length(), str2.length()); 
    } 
    
    public static void main(String[] args) { 
       
        String str1 = "chenlb.blogjava.net"; 
        String str2 = "chenlb.javaeye.com"; 
        System.out.println("ld="+ld(str1, str2)); 
        System.out.println("sim="+sim(str1, str2)); 
    } 
}